Flexible stay-bolt for boilers.



B. E. D. STAFFORD. FLEXIBLE STAY BOLT FORBOILERS.

APPLICATION FILED DEG.13, 1911.

Patented Oct. 29, 1912.

UNITED STAWENT 09 1 v BENJAMIN E. D. STAFFORD, OF PITTSBURGH,PENNSYLVANIA, ASSIGNO R T0 FLANNERY I BOLT COMPANY, OF PITTSBURGH,PENNSYLVANIA.

FLEXIBLE STAY-BOLT FOB, BOILERS.

Specification of lletters Patent.

Patented Oct. 29,19 2.

Application filed December 13, 1911. Serial No. 665,505. r

being to provide a simple and effective de tachable steam tight closurefor the outer end of the bolt, and it consists in the details ofconstruction as will be more fully described and pointed out in theclaims.

In the accompanying drawings, Figure 1 is a view in elevation partlyin'section showing the bolt applied to the. inner and outer sheets of aboiler, and Fig. 2 is a view in plan.

1 represents a bolt having a substantiallyspherical head 2 at one endand threaded at the opposite end, the head 2 being provided with a slot3 for the engagement of a suitable driver.

Secured to the outer sheet 4 of the boiler, is the sleeve or bushing 5,threaded externally, and may be cylindrical, but is preferably slightlytapering externally, so that as it is screwed into the outer sheet 4,the wedging action produces an absolutely steam tight joint. The innerend of this bushing has a bore 'or opening of greater diameter than thebolt 1, and. is made concave, as shown in Fig. 1, below the seat 6within the sleeve or bushing on which the bolt head 2 rests. v

The curvature of the inner surface ofthe bore of the sleeve below theseat, is preferably in the segment of an oval as shown in dotted lines,which form is well adapted for loosening and breakingup incrustation bythe deflection of the bolt.

The bushing 5 receives the head 2 of the bolt 1 and houses the same, andis provided internally'with the seat 6, formed preferably in the arc ofa circle concentric with the head of the bolt, the curvatures of theinner surface of the sleeve or bushing above and below seat 6,permitting of a universal to which the bolt is connected. The cavitywithin the sleeve or bushing 5 above the seat 6, is-of a size suflicientfor the free-entrance of the head, and the outer end of said bushing hasa pointed ridge, preferably in the shape of an inverted V on which therim of' the copper or other soft metal cap 7 rests. This cap maybestamped or cast, and is made of copper, copper alloy or other;comparatively soft metal, so that when forced or compressed against theouter end of the bushing or sleeve 5, the latter will be forced into thesofter metal cap, and the latter will conform itself to the harder metalseat,

and thus form a steam tight joint.

The capis concave on its inner face and .is sufliciently removed fromthe bolt head to afford clearance for the movement of the bolt due toexpansion of the sheets, and is provided centrall on its outer surfacewith an angular, pre erably' hexagonal boss 8, adapted to be engaged bya wrench whereby the cap may be .turned on its seat, before it is fullyclamped in place, to clean its bearing surface and the bearing surfaceof the bushing or sleeve. This cap is also provided on its outer surfacewith an annular shoulder 9 adapted to be engaged by the lip 10 of theclamping nut 11. This nut is threaded at its lower end to engage theexternal threads on the upper end of the bushing or sleeve, and isprovided internally, intermediate its lower end and its overhangin lip10, with an annular rib 12, which ums an abutment or bearing for therimof the cap 7,. and prevents-the latter from spreading or crushingunder the clamping action of the nut. This nut overhangs the cap 7within the plane of the clamping lip 10, but is removed from said cap soas to permit the latter to give or bulge under excessive pressure, butover movement of the head on its seat during 7 the expansion andcontraction of the sheets packing thus dispensing with a separate gasketwhich is used to secure a steam tight joint.

By employing a cap of softer metal than the bushing and its nut, lexpedite the handling of the parts and obtain a perfect fit between theparts Without the employment of gaskets or any other packing.

1 make no claim in this application to a stay bolt structure comprisinga bolt having a head, a sleeve or bushing having an internal seat forsaid head, a soft metal capforming a closure for the sleeve or bushing,and a nut for locking the cap to the bushing, as the same forms thesubject matter of my pen-ding application No. 665,504 filed December13th, 1911. 7

It is evident that many slight changes might be resorted to in therelative arrangement of parts shown and described Without departing fromthe spirit and scope of the claims annexed. Hence I would have itunderstood that I do not Wish to confine myself except as required bythe scope of said claims to the exact construction and ar- 11;angernentof parts shown and described,

ut, I

Having fully described my invention What oaaaaa I claim as new anddesire to secure by LettersdPatent, is

' 1'. A stay bolt structure comprising a bolt having a head, a sleeve orbushing having an internal seat for said head, and also provided With aninverted V-shaped upper end, a soft metal cap seated on said invertedVshaped end, and a nutscrewed to the sleeve or bushing and provided Withan annular lip resting on the rim of the cap, and With an annular ribadapted to form an abutment for the rim of the cap.

2. A stay bolt structure comprising a bolt having a head, a sleeve orbushing having an internal seat for said head, a soft metal cap having acentrally located external angular boss, the said cap being mounted onsaid sleeve or bushing and forming a closure for same, and a nut forlocking the cap to the bushing.

In testimony whereof, I have signed this specification in the presenceof two ,subscribing Witnesses.

BENJAMIN E. D. STAFFORD.

